SEOUL, South Korea — The coronavirus spread to more countries and the numbers of new cases and deaths outside of China climbed, with special concern focused on South Korea, where infections doubled in a single day — raising fears that another Asian country was losing control of the escalating epidemic.
By Saturday, the virus had been identified in two new countries, Lebanon and Israel, bringing the spread to 28 countries, with about 1,500 confirmed cases outside of China, where it originated. The death toll in Iran rose to six, the highest outside of China, and the number of confirmed cases there reached 28, though experts suggest that the real number is likely to be far higher.
South Korea’s prime minister, Chung Sye-kyun, called the situation in his country “grave” and urged citizens to cooperate with the government and avoid large political gatherings, which have continued in the capital, Seoul, despite a city ban.
“The government will sternly deal with acts that interfere with quarantine efforts, illegal hoarding of hygiene goods and acts that spark uneasiness through massive rallies,” Mr. Chung warned in a nationally televised address.
The spike of cases in Korea and the rising death toll in Iran raised fears that the window to avert a global pandemic was narrowing. The World Health Organization warned African leaders of the urgency of preparing for the virus, and identified 13 African countries as priorities because of their direct links to China and the high volume of travel between the countries.
The number of confirmed infections in South Korea, after more than doubling on Saturday, rose to 566 on Sunday morning. More than half were among members of a secretive religious sect, the Shincheonji Church of Jesus, and their relatives and other contacts. Most of the cases are centered in and near Daegu, the country’s fourth largest city, which has been placed under a state of emergency.
Between Daegu, a city of 2.4 million people, and a nearby province where the sect’s members often do volunteer work, 465 people have tested positive.
In the neighborhood of the sect’s church in the city, banks, coffee shops, restaurants and convenience stores have all shut down, rendering it a ghost town. Across the city, department stores, shopping alleys and traditional outdoor marketplaces have all been drained of shoppers.
The only busy sites were government-run health centers, where citizens lined up to find out whether they were infected.
The scare deepened across South Korea as the number of patients soared and two more deaths from the virus were reported.
A 40-year-old worker at an auto-parts factory in Gyeongju, a city near Daegu, was found dead at his home on Friday evening. He was posthumously confirmed on Saturday to have been infected with the coronavirus. A 56-year-old patient from a hospital in Chengdo, another town near Daegu, died on Sunday, health officials said.
On Friday, the first reported case in Busan, South Korea’s second largest city, caused public libraries, horse racetracks and facilities for senior citizens to close. Many churches offered services only online. Others stayed open, but skipped hymns or “Amens” to limit the possibility of congregants’ exposure.
The cities of Chuncheon and Ulsan reported their first cases on Saturday, and the national news agency Yonhap reported that people there were emptying shelves of rice, instant noodle, eggs and other essential food items.
The number of coronavirus cases in South Korea also set off alarms in Israel, after nine South Korean visitors tested positive for the virus upon returning home. They had spent a week touring popular, often-crowded Israeli religious sites. On Saturday, Israel tightened its border and barred South Korean travelers.
Discussions whether to allow other flights from South Korea to Tel Aviv were planned for Sunday, Kan radio said. Health officials were working with the tourism ministry and travel agencies to book flights back to South Korea for the 1,700 South Korean tourists in Israel.
In the United States, State Department officials said that thousands of Russia-linked social media accounts were spreading disinformation about the coronavirus, including a conspiracy that the United States was behind the outbreak, State Department officials said.
Two senior American officials said that the repatriation this week of 14 American citizens from the cruise ship Diamond Princess who had tested positive for the coronavirus had infuriated President Trump. Mr. Trump is a self-declared “germaphobe.”
William Walters, a top medical official at the State Department, told reporters that the decision to fly the 14 back had been made by the State Department in consultation with Robert Kadlec, an assistant secretary at the Department of Health and Human Services.
The evacuation of more than 300 Americans was already underway last Sunday when Japanese officials informed American counterparts of the laboratory test results, he said.
The decision to fly back the infected passengers was made over the objections of officials at the Centers for Disease Control and Protection.
The C.D.C. also had advised American passengers of the Westerdam cruise ship, where a passenger was found to have the coronavirus, that they were not required to self-quarantine and were no longer subject to travel restrictions. No other infections were found among passengers on the ship, the C.D.C. confirmed.
An American woman, 83, who had disembarked from the Westerdam in Cambodia along with thousands of others passengers and crew members, had tested positive for the coronavirus after arriving at the airport in Kuala Lumpur, Malaysia on Feb. 15.
The woman’s diagnosis had raised concerns and worries that another vector of transmission was going global and Cambodia has called the Malaysian diagnosis flawed.
By Saturday, the patient had been cleared of the coronavirus and was being monitored in the hospital with a “slight cough” after an antiretroviral treatment, said Noor Hisham, the Malaysian health director general.
Cambodia’s prime minister, Hun Sen, said the woman never had coronavirus. The prime minister is a close ally of China and he has cast doubts on the seriousness of the coronavirus outbreak.
The rise in Iran’s death toll came days after the country had insisted that it had no coronavirus cases. Kianush Jahanpur, the head of public relations at the country’s health ministry, wrote in a tweet that most of the infections came from Qom, 80 miles south of the capital, Tehran. Cases were also reported in Tehran and the northern city of Rasht.
On Saturday, state media reported that universities would be closed in 10 provinces for a week and movies, concerts and other cultural events were canceled countrywide for a week.
Dr. Tedros Adhanom Ghebreyesus, the World Health Organization’s director, said the organization was “especially concerned” about the cases in Iran.
The spread of the virus is a concern as Iran holds parliamentary elections this weekend. Many voters in Qom lined up in front of the voting stations wearing masks according to videos from Iranian news agencies.
With confirmed cases rising in Asia and in the Middle East, the W.H.O. confirmed on Saturday that its experts were being allowed into Wuhan, the city at the center of the coronavirus epidemic, for the first time.
Choe Sang-Hun reported from Seoul and Derrick Bryson Taylor from New York. Reporting was contributed by Hannah Beech from Bangkok, Farnaz Fassihi from New York, David M. Halbfinger from Jerusalem, Elian Peltier from London and Edward Wong from Washington.